Probability with huntington's disease?
huntington disease is a rare degenerative human disease determined by a dominant allele, hd. the disorder is usually manifested after the age of 45. a young man has learned that his father has developed the disease; his mother does not have the disease (and does not carry to hd disease allele).
what is the probability that the young man will later develop the disease?

if the young man has a child with a woman who does not carry the hd disease allele, what is the probability that their first child will be affected by huntington disease as